She also said her vote it is not based on language she added to the bill that would spare Louisiana the loss of some $300 million in federal Medicaid funding.

"My vote today to move forward on this important debate should in no way be construed by the supporters of this current framework as an indication of how I might vote as this debate comes to an end," Landrieu said. "It is a vote to move forward to continue the good and essential and important and imperative work that is underway."

She continued: "After a thorough review of the bill over the the last two-and-a-half days, including many lengthy discussions, I have decided there are enough significant reforms and safeguards in this bill to move forward, but much more work needs to be done."

Landrieu, who chairs the Senate Small Business and Entrepreneurship Committee, has been especially concerned that the bill as written does not do enough to quickly and dramatically rein in soaring health care costs for small business.

Landrieu said she withheld her commitment for as long as possible to extract as many concessions as she could, and she can be expected to continue to press for changes in the bill in the days and weeks ahead.

At the end of her remarks, after speaking for 14 minutes outlining the strengths and weaknesses of the bill as now written, Landrieu also took a few minutes to defend herself from attacks by what she characterized as "some very partisan Republican bloggers."

Some commentators have essentially suggested Senate Majority Leader Harry Reid, D-NV, had "bought" Landrieu's vote - some have dubbed it "the Louisiana purchase" - by permitting her to insert language into the bill that would specifically benefit Louisiana.

The provision would protect the state from the full effects of what the Jindal administration has warned would be a devastating drop in federal Medicaid funding in 2011 due to an anomalous spike in per capita income in the state because of a rush of recovery money into the state in the aftermath of Hurricanes Katrina and Rita.

The Congressional Budget Office priced the so-called "FMAP" fix for Louisiana at $100 million, but Landrieu said she expects it will bring $300 million in additional Medicaid funding to the state.

In her floor remarks, Landrieu explained that the unusual infusion of money into the state, and a temporary surge in wages in the constricted labor market after the disasters, led to a distorted picture of Louisiana's economic circumstance, throwing out of whack the formula for determining how much federal Medicaid aid the state should receive.

"It made us seem like we were Connecticut and not Louisiana, like we had some kind of time overnight become rich; that is not the case," said Landrieu. "Our state is as poor as it was if not poorer, and I am not going to be defensive about asking for help in this situation."

Furthermore, she said, "it's not a $100 million fix, it is a $300 million fix, and it is the No. 1 request of my governor, who is a Republican, and it is unanimously supported by every member of our delegation, Democrat and Republican."

"I am proud to have asked for it. I am proud to have fought for it," she said. But, she said, it did not determine her vote. "That is not the reason I am moving to debate."

The Senate began debate at 10 a.m. heading toward a pivotal 8 p.m. vote on whether to allow debate to proceed after the Senate returns from the Thanksgiving holiday.

Landrieu's announcement shifted all eyes to Lincoln, who faces an even tougher political choice because, unlike Landrieu, who won a new six-year term last year, Lincoln is up for re-election next year. About two hours after Landrieu announced her decision, Lincoln also said she would vote to allow debate to proceed, rather than vote to simply "walk away" from the issue.

"The vote tonight will mark the beginning of consideration of this bill, not the end," Lincoln said.

Every Republican opposes continuing debate on the measure.

Sen. David Vitter, R-LA, who spoke less than an hour before Landrieu, said that Louisianians see the health care bill as part of a larger power-grab by the federal government.

"Louisianians are also connecting the dots, seeing a bigger picture that really concerns them," Vitter said. "They are connecting the dots of the takeover of banks and insurance companies and car companies with the CEO of GM literally being hired and fired in the Oval Office, and now potentially one-sixth of the U.S. economy through health care."

Noting the bill's estimated $848 billion price tag over 10 years, Vitter said, "if someone started spending a million dollars a day when Jesus Christ was born and continued to spend a million dollars a day, we still wouldn't be up to that figure."

But Vitter said even the CBO estimate figure grossly underestimates the actual and eventual cost of the bill, because the way the bill is being phased in, the CBO score for the first 10 years measures "10 years of tax increases and only six year of spending."

The actual 10-year cost, once spending begins - from 2014 to 2024 - will be $2.5 trillion over that ten years, he said.

"Louisianans see this, Americans see this is a big dot to connect, part of a huge trend of exploding government power and exploding government spending and debt," Vitter said.

Vittter said the inclusion of a public option would provide a "big open door to increasing the federal government role and domination in our economy."

Landrieu is one of a number of centrist Democrats who are adamantly opposed to including any kind of public option in the bill, even one that permits states to opt out. Lieberman, for one, has said he would join a Republican filibuster to block a bill with a public option.

Exactly two weeks ago, the House met on a Saturday to vote on its own health-care overhaul. It passed 220-215, with Rep. Anh "Joseph" Cao, R-New Orleans, the only member of the delegation - and the only Republican in the Congress - to vote for it.